Changeovers between components in a blood circulating system using currently available products constitutes a very difficult and time consuming process during surgery. A typical blood circulating system includes a blood collection device, blood pump and heat exchanger/oxygenator assembly. The system may also include an arterial blood filter downstream from the heat exchanger/oxygenator unit. Such systems are used to oxygenate and circulate blood in a patient during heart surgery.
The heat exchanger/oxygenator assembly (with arterial blood filter, if present) must often be replaced during surgery. Reasons for replacement include leakage, clogging and/or other factors which cause the performance of the components to fall below allowable levels. Even in those situations in which the heat exchanger/oxygenator assembly is functioning properly, a different assembly may be substituted to provide a different function such as a hemodializer, etc.
One problem associated with replacement of a blood treatment assembly such as a heat exchanger/oxygenator or hemodializer is the potential for allowing air to enter the fluid lines connecting the devices. At the least, prime could be lost in the system requiring the operator to prime the system before restarting. At the worst, air in the system can cause strokes or death in patients should the air be allowed to enter the patient's bloodstream.
Another problem with replacement of the assembly is the complex and time-consuming procedure which must be performed to accomplish the changeover between assemblies. Such changeovers typically require the operators to: (a) stop the flow of the blood pump; (b) clamp all circuit lines to and from the components to be replaced; (c) drain all blood in the circuit lines into a reservoir; (d) remove the heat exchanger/oxygenator assembly from a mounting bracket; (e) remove the arterial blood filter, if present, from a mounting bracket; (f) mount the new heat exchanger/oxygenator assembly and arterial blood filter (if necessary); (g) prime the new components with saline solution; (h) open the clamped circuit lines; and (i) restart flow from the blood pump.
The above procedure typically takes four to ten minutes to complete. As a result, the cost to patients is increased along with an increase in patient morbidity due to the lengthened surgery time.
In addition to the increased time and complexity, the procedures also offer the opportunity for leakage of blood from the system due to improperly clamped circuit lines and/or unsealed ports on the components being removed. In many instances, the blood can be under pressure in the fluid lines, which increases the likelihood that it will leak or even spray from the fluid lines during changeovers. Exposure to blood is a significant concern for medical personnel as the blood can expose them to, among other diseases, hepatitis and AIDS. An additional problem is contamination of the circuit lines during the changeover procedure, as those lines must be reconnected before operation of the system can resume.
The present inventor's prior applications and issued patents, i.e., U.S. Pat. Nos. 5,149,318; 5,254,080, and 5,304,164 and 5,399,156 all of which are hereby incorporated by reference, have addressed issues surrounding conversion of devices which handle a patient's blood during surgery to devices which are useful during post-procedure care. As such, the apparatus described therein include connector blocks which can be replaced to convert the devices for different operations. Those connectors do not, however, offer the ability to replace components within the blood circulating system during an operation.